Metal protecting compositions



Patented Jan. 15, 1952 METAL PROTECTING COMPOSITIONS John C. Zimmer,Union, and Gordon W. Duncan,

Westfleld, N. J., assignors to Standard Oil Development Company, acorporation of Delaware No Drawing. Application November 5, 1949, SerialNo. 125,836

3 Claims. (Cl. 106-14) The present invention relates to compositions ofmatter containing petroleum products and, more particularly, tolubricants and other predominantly petroleum products adapted to theprotection of metals from various causes of corrosion.-

The application of an unctuous coating for the protection of metalsurfaces, both external and internal, is an established practice.Compositions composed solely of hydrocarbon compounds have been used forslushing metallic surfaces, but they are not wholly effective becausethe films produced therefrom are not impervious to moisture,particularly under high humidity conditions where moisture is condensingon the film. In order to overcome this difficulty and to increase theeffectiveness of the coating film, it has been suggested that. materialsin the nature of metal soaps be included in the hydrocarbon composition.Even though thes metal soaps materially increase the effectiveness ofhydrocarbon coating compositions, the resultant slushing compound isobjectionable for certain types of uses. The objection arises throughthe fact that these soaps are ash-forming materials. If the protectivecoating containing metal soaps is employed on metal parts which are tobe subsequently subjected to relatively hightemperatures accompanied byconsiderable wear, such as, for instance, the pistons and cylinder wallsof an internal combustion engine or the barrel, firing mechanism andbreech of fire arms, then it is necessary or desirable to completelyremove the protective coating before placing the protected article inservice, otherwise the protective coating will be burned-off, leaving anabrasive ash which will cause more rapid wear, necessitating morefrequent overhauling and replacement.

An object of the present invention is the formation of a non-dryincomposition of matter for arresting, preventing and inhibiting thecorrosion of metals, particularly ferrous metals, which composition willnot form a combustion ash on being burned. This and other objects willbe apparent to those skilled in the art upon reading the followingdescription.

Corrosion inhibitors are known in the art. Typical examples of patentliterature are the patents to Sloan, Patent No. 2,333,206 and to Wassonet al., Patent No. 2,401,993. In the prior art there is disclosed thatlong chain aliphatic amines may be used to protect metals againstcorrosion. There is also taught that a rust preventative may be formedby reacting a primary straight chain aliphatic amine having from 8 to 14carbon atoms with an organic acid having a carboxyl group attached to acyclic nucleus.

It has now been found that the reaction products of certain basicnitrogen compounds and sulfonic acids provide, in conjunction withpetroleum hydrocarbons, a very effective means for protecting metalsagainst the ravages of corrosion. The nitrogen bases employed in makingthe sulfonates of the present invention are selected from the primaryamines such as methyl amine, ethyl amine, propyl amine, lauryl amine oroctadecenyl amine; secondary amines, such as dimethyl amine, diethylamine, dipropyl amine, dilauryl amine, etc.; tertiary amines, such astrilauryl amine; polyamines, like ethylene diamine and lauryl diamine;heterocyclic nitrogen bases such as pyridine, quinoline andhydrocarbon-substituted imidazolines or oxazolines, and quaternaryammonium bases of the type of dimethyl octyl benzyl ammonium hydroxideand tetramethyl ammonium hydroxide. In general, alkyl or alkenylsubstituted nitrogen bases are preferred because of their improvedsolubility over aromatic naphthenic and alkylol derivatives, and ofthese, it is preferred to use the alkyl compounds wherein the alkylgroups contain from 1-5 carbon atoms, the methyl amine being especiallypreferred.

The sulfonic acids can be preferentially watersoluble petroleum sulfonicacids also known as "green acids and preferably the preferentiallyoil-soluble petroleum oil sulfonic acids also designated as mahoganyacids. The sulfonic acids having a molecular weight of from 350 to 600are operable and those having a molecular weight of from 400 to 500 arepreferred.

The sulfonic acids are produced by the action of fuming sulfuric acid onpetroleum oil. The following example describing the action of fumingsulfuric acid on a mineral oil distillate will sufliciently illustrateone method of obtaining sulfonic acids. A petroleum oil distillate,preferably one which will produce a white oil having a viscosity of from150-500 S. S. U. at F., after complete sulfonation, is treated with fromabout 7-10 pounds of fuming sulfuric acid per gallon of oil, dependingupon the degree of sulfonation desired, in successive 1-2 poundincrements or dumps per gallon of oil. The temperature during the acidtreatment is maintained at or below about 100 F. After each increment offuming sulfuric acid has been added to the oil and agitated to furnishcontact between the acid and the oil, the acid is permitted to settle asan acid sludge which is removed 3 before the next increment of fumingsulfuric acid is addedto the oil. After all of the fuming sulfuric acidhas been added to the oil and the oil freed of acid sludge, theacid-treated oil containing the preferentially oil-soluble sulfonicacids dissolved therein is in condition for further treatment designedto remove the oil-soluble sulfonic acids. The oil-soluble sulfonic acidscan be recovered from the acid oil either by solvent extraction orneutralization followed by solvent extraction. If solvent extraction isemployed,

. the acid oil is agitated with an alcohol such as ethyl alcohol orisopropyl alcohol or with phenol or other appropriate solvent, whichdissolves out the oil-soluble sulfonic acids, forming, on standing alower liquid phase of solvent and sulfonic acid. removable from theupper oil phase by decantation. The solvent can then be recovered bydistillation or the sulfonic acids may be neutralized with the organicbase before recovery of the solvent by distillation. The more commonprocedure is to neutralize the acid-treated oil with aqueous sodiumhydroxide or other alkali, thus forming an oil-soluble sulfonate soap inthe oil. The neutralized oil is then treated with a solvent for thesoap. such as aqueous alcohol of about 60% strength. An alcohol layercontaining dissolved sulfonates is then separated from the oil andsubsequently distilled to recover the alcohol and remove water. Insteadof aqueous alkali, the acid-treated oil can be neutralized with basicnitrogen compounds to form the sulfonates of the present inventiondirectly, and these sulfonates can then be recovered from theneutralized oil by solvent extraction with a solvent such as alcohol orphenol.

Other methods of making the amine sulfonates of the present inventioninclude the direct neutralization of sulfonic acids as such and a doubledecomposition reaction with metal sulfonates such as sodium or calciumsulfonate. Where direct neutralization is employed, the reactionproceeds quite rapidly at atmospheric temperatures. In the case wheremetal sulfonates are used as the source of the sulfonate ion, the metalsalt can be decomposed with a mineral acid such as hydrochloric orsulfuric acid and then neutralized with a basic nitrogen compound; orthe metal sulfonate may be reacted with an amine salt as, for instance,methyl amine hydrochloride. A ready means of preparing an aminesulfonate is illustrated below.

Example 1 1500 grams of a 30% solution of sodium sulfonate (450 mol.wt.) in oil was blended with one mol equivalent of lauryl amine (186 g.)and the solution comingled with one mol equivalent of hydrochloric acid(37 g.) as a aqueous solution. The resultant emulsion was then heated to300 F. to evaporate the water employing one drop of a silicone polymerto control foaming, and the mixture filtered through a filter aid toremove the sodium chloride which results from the neutralizing reaction.Analysis of the product showed a sodium content of 0.06%, indicatingabout 96% conversion of the sodium sulfonate to the amine derivative.

The improved metalprotecting compositions of the present inventioncontain in addition to the above-described nitrogen base sulfonates, theusual constituents of a protective base material, which generallyinclude a non-siccative oleaginous material such as a mineral oilproduct which may be either a light mineral oil distillate,

amineral oil of about lubricating consistency or a more resistantnon-drying coating material such as petrolatum or any of the variouspetroleum waxes. Also waxes and oils of animal origin, such as degras orlanolin, or of vegetable origin, such as carnauba wax, may be used inthe base material if desired. Heavy viscous rust preventive compositionssuch as those containing petrolatum or other waxes, may be diluted witha volatile solvent if necessary to facilitate application. In manyinstances it may be desirable to include auxiliary agents in the rustpreventive composition. Among such auxiliary agents there may bementioned carboxylate soaps, phosphorus compounds, metal sulfonates suchas calcium soaps of mahogany sulfonic acids; 'metal phenates, metalphenol sulfides, natural fats and oils such as wool fat, etc. Forspecial purposes, such as to enable the composition to dislodge waterfrom metal surfaces, polar compounds such as alkylol amines, alcohols,esters, ethers, ether alcohols and the like may be incorporated in thecomposition. In still other instances thickeners such as polyisobutene,acrylic acid ester polymers. copolymers of styrene and olefins ordiolefins; ester polymers, metal deactivators, dyes, oiliness agents,extreme pressure additives, bearing corrosion inhibitors, anti-oxidantsand grease-forming soaps may be desirable.

Those compositions of the present invention in which the base materialis of lubricating oil consistency will be found to be useful not onlyTest procedure Sand blasted panels of hot rolled steel are dipped intoslushing compound samples, then maintained vertically in a box for 16hours under ordinary room conditions to allow the rust preventive filmto reach an equilibrium condition. Compounds containing petrolatum orwaxes are applied at temperatures above their melting point and fluidproducts are applied at room temperatures. The coated panels are thenplaced and spaced apart in an upright position in a humidifier chamber,wherein at F. they are subjected to continuous moisture condensation.The time, in hours, for a panel subjected to these conditions to developinitial evidence of rusting is observed and recorded as the resistancelife of the coating composition.

The following data illustrate the rust preventive effectiveness of thepresent invention:

Ilours to Corrosion Test Material Base Oil 1 1. Base il+5% lauryl amino3-147 (crmlic pcrlornmnuindicates borderline quality). Base 0il+5%lanryl nmine sullmmte 3-27.

Base 0il+5% lauryl amine salicyiatm 3. Base Oil+5% methyl aminesulfonate 41] -l'.

1 Base Oil=Extractcd Coastal distillate of SAE 30 grade.

1 From a petroleum sull'onic acid having a molecular weight of 430 Anexamination of the data reported above shows that the material of thisinvention is outstandingly superior to either the long chain amine orthe long chain amine salicylate.

The organic nitrogen base sulfonates of the present invention are alsoeffective in preventing corrosion to metals resulting from the use ofchlorine containing lubricants or solvents; they are useful as ash-freeengine oil detergents; serve to stabilize leaded gasolines against leadprecipitation and to prevent corrosion of fuel containers resulting fromwater contamination. The organic nitrogen base sulfonates of the presentinvention will also be found to be useful as steam cylinder oilemulsifiers and detergents, soluble oil emulsifiers, asphalt wettingagents, wax modifiers, rubber plasticizers and grease modifiers.

' ventors.

What is claimed is:

l. A non-corrosive metal protective composition consisting essentiallyof from to 99% by weight of a mineral base lubricating oil and from 1%to 10% by weight of methyl amine petroleum sulfonate wherein themolecular weight of the uncombined petroleum sulfonic acid is between350 and 500.

2. A composition according to claim 1 wherein the methyl amine petroleumsulfonate is derived from a petroleum sulfonic acid having a molecularWeight of about 450.

3. A rust preventative composition which consists essentially of about97% by weight of a mineral base lubricating oil and containing combinedtherein about 3% by weight of a methyl amine petroleum sulfonate made bycombining a methyl amine with a salt of a petroleum sulfonic acid havinga molecular weight of about 450.

JOHN C. ZIMMER. GORDON W. DUNCAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,398,193 sharp Apr. 9, 19462,412,634 Schwartz Dec. 17, 1946

1. A NON-CORROSIVE METAL PROTECTIVE COMPOSITION CONSISTING ESSENTIALLYOF FROM 90% TO 99% BY WEIGHT OF A MINERAL BASE LUBRICATING OIL AND FROM1% TO 10% BY WEIGHT OF METHYL AMINE PETROLEUM SULFONATE WHEREIN THEMOLECULAR WEIGHT OF THE UNCOMBINED PETROLEUM SULFONIC ACID IS BETWEEN350 AND 500.